Biointerfaces Mediated by Molecular Bonds: Cohesive Behaviors

We investigate the cohesive response of biointerfaces mediated by noncovalent receptor-ligand bonding under monotonic, cyclic or other types of loading. By examining the spatiotemporal evolution of the state probability distribution that describes the collective association and dissociation kinetics of interfacial bonds, we show that such interfaces resist the imposed surface separation in a strongly rate-dependent manner. Remarkable hysteresis is exhibited when the interfaces are exposed to single stretching and relaxation cycles at high loading rates, and this hysteretic response shifts in consecutive multiple cycles. There generally exists an optimal ramping velocity that gives rise to the maximum energy dissipation at the interfaces. These results should be useful in understanding the cell-matrix adhesion and de-adhesion phenomena under dynamic and repetitive forces, as well as the adhesion-mediated cellular behaviors such as migration and reorientation.